2) The scoop MUST be

out of the boundary layer for the internal diffuser to work properly. I

suggest some reasonable

lip radii and a splitter to separate the boundary layer.

Jeff Spitzer

Mike Wills wrote:

  How significant is the boundary layer effect in a tractor config with the
rad under the engine and a chin scoop directly under the spinner? Seems to
me that the further back on the airframe the inlet is, the more significant
would be the effect. Is it really necessary to use a splitter with a chin
scoop? There seems to be some confusion on the part of industry as well as
Ive seen a number of turbine powered aircraft with chin inlets and no
splitter, as well as some that do incorporate a splitter.

Mike Wills

Jeff Spitzer wrote:

If I were doing a chin scoop and there was no bumps, gaps or otherwise
between where the air first encountered the cowl and the scoop then I would
not use a splitter.  The primary difference for a chin scoop is the highly
favorable pressure gradient (pressure dropping rapidly the whole distance
from initial impact to scoop) that the boundary layer is exceptionally thin
and energized.

Jeff Spitzer

 
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